Can you set maximum charge?

I am considering buying a used electric car. The 2013 LEAF and Ford Focus Electric (FFE) cars are my top picks. From the reading I have done it looks like avoiding full charge and full discharge cycles are very important for battery life. So can you set a maximum charge percentage for the FFE?

Some of what I have found: From the Idaho National Laboratory's Advanced Vehicle Testing Activity it looks like the FFE has about 95% of its advertised battery capacity after 14 months and 12,000 miles. The 12 volt accessory battery in the FFE seems to be a problem. The LEAF has about 85% of its battery capacity after 15 months and 15,000 miles. Reading forums such as this one, shows that high mileage commutes are hard on both the FFE and LEAF. The FFE seems to do better with low mileage commutes than the LEAF.

Any suggestions?

plcfischer said:

Any suggestions?

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Firstly, just speaking for mere driving enjoyment... get the Leaf if you want to feel like you're driving on balloons, or get the FFE if you want a more sporty, firm feel.

The FFE has no "max charge" setting, but as near as we can tell, the FFE only charges to about 90% for the actual total battery capacity anyway. The FFE always maintains a "buffer" of about 10% of the total capacity either at the "top" or "bottom" of the battery. In other words, when the FFE tells you "100% fully charged", it really means the battery is charged to somewhere around 90% of its actual total capacity. Likewise, when the FFE tells you "0% charge remaining", it really means the battery still holds around 10% of its actual total capacity. You can't use the remaining buffer, as the car will stop shortly after it tells you "0%".

Basically, the car's 0-100% displayed range is mapped to (roughly) the middle 80% of the total actual battery capacity. This is already a pretty optimized use of the battery and it doesn't seem really worth the effort to attempt to "manage" this better manually. As always, however, YMMV, and everything I say here is IMO.

As far as I know, the 12-volt battery problems were solved a while ago with firmware updates. Whatever FFE you buy, if you buy one, make sure it is either a recent model year, or has had all recall work and firmware updates applied.

I have had my 2013 FFE (since new) for nearly three years now. For the first year or so, it seemed that I had not experienced any battery fade. But, I think now I most certainly have. Nevertheless, I have (and continue to) really enjoy the car.

I also didn't experience any 12-volt battery issues.

I can attest to the 12V battery issue being fixed. Shortly after having the latest firmware update I left my car plugged into a L1 charger while I traveled. I came back 4 days later to discover I had left my parking lights on. I'm fairly certain that whatever the firmware update they did the 12V must be periodically monitored and the charger comes on as needed to keep it topped up. That's the only thing I can think of to explain why I didn't have a dead battery. The charger was not on when I got back to my car either so it's not like it was just constantly charging the 12V battery.

I'd also check to see if there are any FFE available in your area. This will likely be the biggest hurdle. Leaf's probably outnumber FFE by 100 to 1. You will not likely find a used FFE in most markets.

triangles said:

I can attest to the 12V battery issue being fixed. Shortly after having the latest firmware update I left my car plugged into a L1 charger while I traveled. I came back 4 days later to discover I had left my parking lights on. I'm fairly certain that whatever the firmware update they did the 12V must be periodically monitored and the charger comes on as needed to keep it topped up. That's the only thing I can think of to explain why I didn't have a dead battery. The charger was not on when I got back to my car either so it's not like it was just constantly charging the 12V battery.

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Yes, thats been my experience as well since my 2014 FFE's firmware was updated a year ago.
Before that for the first year, my FFE's 12v battery could get too low several times just sitting for a few days so I had to monitor the voltage daily to not be caught off guard and use an external 12v charger periodically.
But since the firmware update a year ago the 12v battery has maintained normal level daily without anything special, not one case in the past year of it going too low to start.

Though the FFE itself doesn't have any way to set the charge amount, some external home 240V charging stations have a timer capability where you could set it to only charge for say an hour or whatever time would charge it up to the approximate level you want.

MNEV said:

I'd also check to see if there are any FFE available in your area. This will likely be the biggest hurdle. Leaf's probably outnumber FFE by 100 to 1. You will not likely find a used FFE in most markets.

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Currently there are 130 used FFEs in the US, as listed on Autotrader. Change the location to see how close they are to you.

http://www.autotrader.com/cars-for-sale/Used+Cars/Ford/Focus/Kansas+City+KS-66103?zip=66103&showcaseOwnerId=576637&startYear=1981&endYear=2017&modelCodeList=FOCUS&makeCodeList=FORD&listingTypes=used&sortBy=derivedpriceASC&firstRecord=0&searchRadius=0&trimCodeList=FOCUS%7CElectric&numRecords=25

You are absolutely correct in pointing out that high levels of charge are detrimental to battery life. And while it's true that the FFE "full charge" is only about 90% max state of charge, lower levels yet would be far better.

I have complained repeatedly here about the lack of ability to limit charge in the same way Tesla, Kia, Toyota, Chevrolet (yes,the Bolt has this after a fashion) and others do. It's silly that a car that's one big computer requires you to use a timer or walk outside and unplug. The EPA is substantially at fault for this, as their range rating is influenced by the ability to set a partial charge.

The FFE battery definitely fades with time and use. Less than the Leaf, but in line with other liquid cooled batteries. I wilsh the AVT people would do another test. Mine was down very obviously at 54,000 miles and three years in a moderate Los Angeles climate

When looking at the INL test results, don't compare the 12,000 mile capacity with the advertised capacity...compare it with the "when new" capacity. That's a better indication of fade rate. When new, the batteries exceed their advertised capacity. This masks initial fade. Like cars with gas gauges that stay on full for the first 50 miles.

Thanks for the information. I did go back and look at the battery degradation based on initial capacity instead of advertised capacity. So in summary, I think for the same money a used FFE is a better deal than a used LEAF. The bit better battery life is the difference for me. Because the car will be a commuter car the smaller back seat and much reduced cargo capacity is not a big deal. The FFE's better handling and battery life are more important to me than space.

As for availability, there have been two or three FFEs for sale in may area (RTP in North Carolina), but only one today. I can find 25 2013 LEAFs for sale. Nine of the LEAFs and the one FFE are at the same dealership in Greensboro. The FFE is the least expensive of the ten cars at the Greensboro dealership.

Again thanks for the information.